The present invention relates to the distribution of AC power, and more particularly to apparatus for conditioning the power delivered and reducing energy usage.
Transient surges are common on all power systems. Lightning, generator switching, and major power line shorts are examples of externally generated surges. Transients up to twice the applied voltage are common and up to 50 times the applied voltage have been observed.
More common and more frequent are transient surges caused by inductive load devices such as motors, transformers, relay coil and fluorescent light ballasts. These are known as internally generated surges.
Various transient voltage surge suppressors are well known in the art. U.S. Pat. Nos. 4,152,743; 4,259,705; 4,584,622; 4,587,588; 4,739,436; 4,760,485; 4,777,555; 4,802,055; 4,845,580; 4,866,560; 4,870,528; 4,870,534; and 4,901,183 illustrate various transient voltage suppression systems, surge suppressors, and filters for use in the distribution of electrical power. These patents disclose circuits that use devices such as capacitors and varistors between power lines together with chokes in series with the power lines to filter AC power. None of these references discloses or suggests the provision of inductors across power lines or across a power line and the neutral line of a power source. These patents also fail to disclose apparatus for substantially reducing energy consumption.
Any load that requires a magnetic field to operate, for example motors, transformers, fluorescent lamp ballasts, solenoids, and the like will cause the phase relationship between voltage and current supplied by the utility to change. Such phase shifting reduces the efficiency of the load, resulting in increased power consumption.
The phase angle between voltage and current is called power factor. Inductive circuits have a lagging power factor because the current lags the voltage. Capacitive circuits have a leading power factor because the current leads the voltage. It is desirable to make the angle between voltage and current approach zero. When voltage and current are in phase, the power factor is unity and the most efficient utilization of the power distribution system is obtained.
It would be advantageous to provide apparatus for conditioning AC power to eliminate transients and surges and reduce the energy consumed by inductive and capacitive loads. It would be further advantageous if such apparatus improved the power factor at one or more loads coupled to an AC power distribution system. The present invention provides such apparatus.